Using Static Public IPs and Private DHCP IPs on the Same Router

view story

http://serverfault.com – I have a subnet of public IP addresses that my ISP has provided me with. They are routed through my router (how profound) that has a a static IP. I have successfully assigned the IPs from that subnet to various devices on my network. This works just fine, they get their own public IP, they can access the Internet, and the Internet can access them. However, I would like to also assign some private IPs on my network through that same router and put them behind NAT. Is this even possible? Could a VLAN be of use? I would like to avoid putting another router on the network, which makes this is quit ()